The pair were often at loggerheads during Benitez's spell in charge of Liverpool and Mourinho drew the ire of the Spaniard earlier this week by suggesting Juventus should not consider winning the UEFA Europa League a success.
Benitez - twice winner of the competition with Valencia and then Chelsea last year - was less than impressed with the Portuguese's remarks.
"He talks too much," he said. "Whereas I like to let facts do the talking.
"At Liverpool I knocked his Chelsea out of the Champions League when we had half his money."
Napoli host Juve in Serie A on Sunday, and Benitez says his side are lacking their opponents' experience in winning titles.
"Juve have a winning mentality, but they needed time to achieve that," he said.
"It’s also true that €30 million revenue allows you to buy the best players in the world. That too is a winning mentality.
"They have a squad that allows them to always compete for silverware. Napoli mustn't be a club who focus on winning a competition once every 10 years.
"We need to keep improving, year by year. The squad is having a good season, but Roma and Juve are doing better than we are.
"In order to go for the Scudetto we need more quality and belief. We have lacked that winning mentality."
